Income Taxes - Schedule of Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S. Federal tax benefit at statutory rates	$ (1,925)	$ (2,889)
Impact of:
Tax credits	(715)	(517)
State income tax	(108)	10
International operations	409	30
Share-based compensation	348	2
Valuation allowance	1,471	2,280
Expiration of tax attributes	475	217
Goodwill impairment		784
Other, net	61	96
Total Income tax expense (benefit)	$ 16	$ 13
U.S. Federal tax benefit at statutory rates	21.00%	21.00%
Impact of:
Tax credits	7.80%	3.80%
State income tax	1.20%	(0.10%)
International operations	(4.50%)	(0.20%)
Share-based compensation	(3.80%)
Valuation allowance	(16.00%)	(16.60%)
Expiration of tax attributes	(5.20%)	(1.60%)
Goodwill impairment		(5.70%)
Other, net	(0.70%)	(0.70%)
Tax expense and effective tax rate	(0.20%)	(0.10%)